It will be at least a year before new rules for energy storage take hold for most ISOs and RTOs.

The storage floodgates are opening, but they are not opening quickly.

A review of compliance filings submitted by grid operators in response to the Federal Energy Regulatory Commission’s Order 841 shows that Independent System Operators (ISOs) and Regional Transmission Organizations (RTOs) are complying with FERC’s directive, but work remains to be done.

When FERC issued Order 841 in February, it was hailed as a landmark decision that would open the floodgates for energy storage. That’s still expected to happen, albeit slowly.

Order 841 directs ISOs and RTOs to come up with rules to open up their wholesale energy, capacity and ancillary services markets to energy storage resources on a nondiscriminatory basis. Grid operators had to submit their compliance filings by Dec. 3.

“841 is the start, not the end,” Mike Berlinski, director of emerging technologies at Customized Energy Solutions, told Utility Dive. “A lot more work needs to be done to further explore and understand the market interactions.”

Berlinski expects a large amount of energy storage capacity to come online as a direct result of the new rules. The number of projects being proposed is already “an order of magnitude” more than in the past because FERC initiated and is going through this process, he said.

The timeline for that process is another question. In their filings, grid operators requested approval dates from FERC so that they could meet the commission’s Dec. 3, 2019, deadline to implement the rule changes. Stakeholders have until Dec. 24 to comment on the filings.